Growing evidence for an Alzheimer’s smell test?

Loss of smell is often an early symptom of Alzheimer’s disease, and, according to new research published in the Journal of Neuroscience, could possibly serve as a warning sign at the onset of the disease. Previous research has explored the relationship between loss of smell—or olfactory dysfunction—and the accumulation of a protein in the brain associated with both Alzheimer’s and Parkinson’s diseases, and this latest study, conducted by researchers at New York University’s Langone Medical Center, suggests that loss of smell may be one of the first indicators of Alzheimer’s, and, if detected before the disease has progressed significantly, could give physicians the opportunity for early intervention.

In a study of mice genetically engineered to have varying levels of amyloid plaques in the brain—the protein accumulations that can lead to Alzheimer’s—researchers found that, the development of plaques first impacted the region of the brain associated with smell, and that smell sensitivity suffered even with the presence of very small concentrations of amyloids. Mice are often used in Alzheimer’s research due to the similarities with humans in progression of the disease. If the early impact on sense of smell is detectable in humans, it could be key to developing new, inexpensive diagnostic techniques such as smell tests, which would enable physicians to catch the disease at its onset, and begin treatment before it has progressed significantly to other areas of the brain.